1. Field of the Invention
The present invention relates to a seat sliding apparatus for sliding a vehicle seat which seat body can be longitudinally moved and particularly relates to an attachment structure for attaching an operation lever to a lock plate.
2. Description of the Related Art
In a seat sliding apparatus of this type, the neighborhoods of the bases of lock plates are rotatably, pivotally attached to the side surfaces of a pair of right and left upper rails fixed to a seat cushion side, respectively. The both end portions of a U-shaped rigid operation lever are fitted into two attachment holes formed at the front side of each of the paired lock plates, respectively.
The respective lock plates simultaneously rotate by operating the operation lever. Lock holes formed at the free end sides of the respective lock plates are engaged with lock teeth formed on a pair of right and left lower rails fixed to a vehicle body, thereby preventing a seat main body from moving in longitudinal direction. In addition, by releasing the engagement of the lock holes with the lock teeth, the seat main body can be moved.
The above-stated conventional technique, however, has the following disadvantages. In the conventional seat sliding apparatus in which the both ends of the operation lever are fixedly attached to the respective lock plates, when a stress acts on the upper rail at the side at which a belt anchor is attached due to a collision or the like, the lock plate at the belt anchor attachment side together with the upper rail at the belt anchor attachment side is pulled upward, followed by the deformation of the floor of the vehicle body.
As a result, the rear end sides of the upper rail and lower rail at the belt anchor attachment side float and the upper and the lower rail are thereby inclined. Here, the upper rail at the other side, i.e., the side at which the belt anchor is not attached, is not applied with a force in floating direction and is not, therefore, inclined. In addition, the lock plates pivotally supported by the respective upper rails are coupled to each other by the U-shaped operation lever. Thanks to this, even when the upper rail at the belt anchor attachment side is inclined, the lock plate therefor is held in an initial state. That is, at the belt anchor attachment side, the lock plate is in the same state as that in which the lock plate rotates in unlocking direction with respect to the lower rail.
At the time of the collision, since a force is applied toward the front side, the lock holes of the lock plates are strongly engaged with the lock teeth of the lower rails, respectively and the locking state is not released, whereby the operation lever is bent and elastically deformed.
After collision, when no more force is applied toward the front direction, the lock plate at the belt anchor attachment side rotates in the unlocking direction only by the operation lever bending amount. As a result, the engagement of the lock holes with the lock teeth may be released to thereby release the locking state.